1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, the method including a process of forming a thin film on a substrate, and a substrate processing apparatus suitable for the process.
2. Description of the Related Art
In one of processes of manufacturing a semiconductor device, a silicon oxide film or a metal oxide film (hereinafter, such films will be collectively referred to as oxide films) is formed by a chemical vapor deposition (CVD) method or an atomic layer deposition (ALD) method. Generally, it is known that electric characteristics of a semiconductor device are improved when films of the semiconductor device are formed at high temperatures. The reason for this may be that the concentrations of impurities of the films are reduced and the quality of the film is improved if the films are formed at high temperatures. For example, there is a method of forming a silicon oxide film (high temperature oxide (HTO) film) at a high temperature of about 800° C. by a CVD method using an inorganic material such as SiH2Cl2 gas and N2O gas (e.g., refer to Patent Document 1).
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2001-85333
However, when a silicon oxide film or a metal oxide film is formed by a CVD or ALD method, a source gas such as a silicon source may undergo self-reaction at a higher temperature to generate a contaminant, or HCl or Cl2 generated from the source gas may act as an etchant to deteriorate film thickness uniformity. Therefore, it may be difficult to form a silicon oxide film or a metal oxide film at a higher temperature by a CVD or ALD method.
There is a method of forming an oxide film by diffusion such as a dry oxidation method or a wet oxidation method. However, as size reduction proceeds, if an oxide film is formed by diffusion, a material (for example, silicon) lying under the oxide film is consumed while the oxide film is formed. Therefore, it may be improper to use a diffusion method to form an oxide film in a small region.